Fix JavaScript code bugs

[mgmacias95]

Hello team,

This PR fixes #370, #371 and #372.

Best regards,
Marta

[mgmacias95]

Make sure an error is returned if stdin parameter in execute.exec is not an object

root@master:/home/vagrant/GitHub/wazuh-api# grep -i execute.exec /var/ossec/api/helpers/request_templates.js
    execute.exec(python_bin, [wazuh_control], data_request, function (data) { res_h.send(req, res, data); });
root@master:/home/vagrant/GitHub/wazuh-api# sed -i "s:, data_request, func:, null, func:g" /var/ossec/api/helpers/request_templates.js
root@master:/home/vagrant/GitHub/wazuh-api# grep -i execute.exec /var/ossec/api/helpers/request_templates.js
    execute.exec(python_bin, [wazuh_control], null, function (data) { res_h.send(req, res, data); });
root@master:/home/vagrant/GitHub/wazuh-api# systemctl restart wazuh-api
root@master:/home/vagrant/GitHub/wazuh-api# curl -u foo:bar "localhost:55000/agents?pretty"
{
   "error": 1,
   "message": "Error executing command: stdin value must be an object: null"
}
root@master:/home/vagrant/GitHub/wazuh-api# tail -n4 /var/ossec/logs/api.log
WazuhAPI 2019-04-16 09:42:23 foo: ::ffff:127.0.0.1 GET /agents
WazuhAPI 2019-04-16 09:42:23 foo: CMD - Error executing command: stdin value must be an object: null
WazuhAPI 2019-04-16 09:42:23 foo: [::ffff:127.0.0.1] GET /agents/?pretty - 500 - error: '1'.
WazuhAPI 2019-04-16 09:42:23 foo: Response: {"error":1,"message":"Error executing command: stdin value must be an object: null"} HTTP Status: 500
root@master:/home/vagrant/GitHub/wazuh-api# sed -i "s:, null, func:, data_request, func:g" /var/ossec/api/helpers/request_templates.js
root@master:/home/vagrant/GitHub/wazuh-api# grep -i execute.exec /var/ossec/api/helpers/request_templates.js
    execute.exec(python_bin, [wazuh_control], data_request, function (data) { res_h.send(req, res, data); });
root@master:/home/vagrant/GitHub/wazuh-api# systemctl restart wazuh-api
root@master:/home/vagrant/GitHub/wazuh-api# curl -u foo:bar "localhost:55000/agents?pretty"
{
   "error": 0,
   "data": {
      "items": [
         {
            "os": {
               "arch": "x86_64",
               "codename": "Bionic Beaver",
               "major": "18",
               "minor": "04",
               "name": "Ubuntu",
               "platform": "ubuntu",
               "uname": "Linux |master |4.15.0-46-generic |#49-Ubuntu SMP Wed Feb 6 09:33:07 UTC 2019 |x86_64",
               "version": "18.04.2 LTS"
            },
            "version": "Wazuh v3.9.0",
            "name": "master",
            "manager": "master",
            "registerIP": "127.0.0.1",
            "lastKeepAlive": "9999-12-31 23:59:59",
            "ip": "127.0.0.1",
            "id": "000",
            "status": "Active",
            "dateAdd": "2019-04-16 08:51:34",
            "node_name": "master"
         }
      ],
      "totalItems": 1
   }
}
root@master:/home/vagrant/GitHub/wazuh-api# tail -n4 /var/ossec/logs/api.log

---
WazuhAPI 2019-04-16 09:44:01 foo: CMD - STDOUT: 543 bytes
WazuhAPI 2019-04-16 09:44:01 foo: [::ffff:127.0.0.1] GET /agents/?pretty - 200 - error: '0'.

Split select input argument by , without using a callback

root@master:/home/vagrant/GitHub/wazuh-api# grep -i select_param.split /var/ossec/api/helpers/filters.js
        select['fields'] = select_param.split(',');
root@master:/home/vagrant/GitHub/wazuh-api# curl -u foo:bar "localhost:55000/agents?pretty&select=id,name,os.platform"
{
   "error": 0,
   "data": {
      "items": [
         {
            "os": {
               "platform": "ubuntu"
            },
            "name": "master",
            "id": "000"
         }
      ],
      "totalItems": 1
   }
}

Set log level in configuration using uppercase characters

root@master:/home/vagrant/GitHub/wazuh-api# grep -i config.logs /var/ossec/api/configuration/config.js
config.logs = "info";
root@master:/home/vagrant/GitHub/wazuh-api# sed -i "s:config.logs = \"info\";:config.logs = \"InFo\";:g" /var/ossec/api/configuration/config.js
root@master:/home/vagrant/GitHub/wazuh-api# grep -i config.logs /var/ossec/api/configuration/config.js
config.logs = "InFo";
root@master:/home/vagrant/GitHub/wazuh-api# systemctl restart wazuh-api
root@master:/home/vagrant/GitHub/wazuh-api# tail -n1 /var/ossec/logs/api.log
WazuhAPI 2019-04-16 09:48:45 : Listening on: http://:::55000